Malaria infections in Eritrea have fallen sharply in the last few years thanks to increased use of bed nets and a drought which has dried up mosquito breeding sites, a senior health official said on Tuesday. "We are working now for further successes, and also to sustain what we have achieved so far," said Tewolde Ghebremeskel, head of Eritrea's National Malaria Control Programme. Data for malaria cases treated at health facilities around the Red Sea state show a fall of nearly 85 percent since 1999 -- down from almost 180,000 reported cases at that time to 28,000 in 2004. Ghebremeskel said the key reason for the decline was the government's distribution of bed nets. Insecticide-treated nets have been shown to cut malaria transmission by up to 90 percent. "We have distributed more than a million nets in the past four years, so the coverage of bed nets really helped a lot," he said. Official estimates put Eritrea's population between 3.5 million and 4.4 million, but some experts say it may be as low as 3 million. --More 1831 Local Time 1531 GMT